Centrifuge



June 14, 1955 E. DENMAN 2,710,718

7 CENTRIFUGE Filed Feb. 5, 1954 s Sheets-Sheet 1 INVENTOR Elmer Den man BY Mama Arr Vs June 14, 1955 E. DENMANY CENTRIFUGE 3 Sheets-Sheet 3 Filed Feb. 5, 1954 INVENTOR Elmer Denmczn United States Patent CENTRIFUGE Elmer Denman, Citrus Heights, Calif.

Application February 5, 1954, Serial No. 408,390

16 Claims. (Cl. 233-4) This invention is directed to, and it is a major object to provide, an improved centrifuge or centrifugal separator, and one which represents modifications of the structure illustrated in my United States Letters Patent No. 2,555,323, dated June 5, 1951.

Another important object of the present invention is to provide a centrifuge. which is especially designed, but not limited, for use to accomplish an effective and individual separation of the solids, oil, and water from an initial fluid mixture comprised of water and a pre-crushed oil bearing vegetable substance such as peanuts, soya beans, olives, or the like.

An additional object of the invention is to provide a centrifuge, for the purpose described, which embodies a novel, vertical axis centrifugal separator unit adapted to be driven at relatively high speed, and which unit includes a structural assembly by means of which the solids, oils, and water are caused to stratify and to feed in separated relation out of said unit.

A further object of the invention is to provide a centrifuge which embodies a novel arrangement for feeding the separate constituents of the initial mixture from the centrifugal separator unit to points exteriorly of the centrifuge; such arrangement including a power driven rotary feeder for the solids.

It is also an object of the invention to provide a centrifuge designed for ease and economy of initial construction and assembly of the parts, and long service when in use, with a minimum of maintenance or being required.

Still another object of the invention is to provide a practical, reliable, and durable centrifuge,'and one which will be exceedingly effective for the purpose for which it is designed. 1

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims. 1

In the drawings:

Fig. 1 is an elevational view of the centrifuge; all but the centrifugal separator unit being in section.

Fig. 2 is an enlarged fragmentarysectional elevation showing the structural details of the centrifugal separator unit.

Fig. 3 is a sectional plan view on line 3-3 of Fig. 2.

Fig. 4 is a fragmentary sectional elevation on line 4-4 of Fig. 3.

Fig. 5 is a fragmentary sectional elevation on line 5-5 of Fig. 3. I

Fig. 6 is 'a fragmentary elevation showing one of the full height impeller fins as secured to the rotary cylinder; the latter being shown only in part, and in section.

Referring now more particularly to the drawings, and to the characters of reference marked thereon, the improved centrifuge comprises an upstanding cylindrical housing 1 carried at the lower end on a base (not shown).

repair a cover 2 which forms the bottom of a dome 3 mounted on said housing.

A centrifugal separator unit, indicated generally at 4, is disposed in the upper portion of the cylindrical housing 1 and projects in part upwardly into the dome 3 through a central opening 5 in the cover 2; said unit being constructed in detail in the manner as will hereinafter appear.

A driven vertical shaft 6 is journaled centrally in the housing 1 below the unit 4; the journal means including a bearing 7 in a vertical cylindrical jacket 8 fixed in said housing in surrounding relation to the shaft 6. The shaft 6 is driven from below and at relatively high speed by any suitable drive means (not shown).

At its upper end the shaft 6 is formed with a solid hub 9 carried in a bushing 10, which hub is splined into, and forms the bottom closure for, a vertically elongated, rotary cylinder 11 which is included in the centrifugal separator unit 4, and which unit comprises, with said rotary cylinder, the following:

An inverted, frusto-conical spinner bowl 12 surrounds the lower portion of the rotary cylinder 11 in concentric relation; such bowl being supported, from below, by a bottom collar 13 threaded on the lower part of said cylinder. The spinner bowl 12 is disposed in the upper portion of the cylindrical housing 1, terminating adjacent but short of the cover 2.

A ring 14 is threaded on the periphery of the bowl 12 at the upper end of the latter, and such ring 14 includes an annular, inwardly projecting flange 15 of limited width.

Inner and outer sleeves, indicated at 16 and 17 respectively, extend-in concentrically spaced relation to each other and to the rotary cylinder 11--upwardly from within the upper portion of the bowl 12; the inner sleeve having an upper end 18 which engages and closes with the cylinder 11, while the outer sleeve 17 includes an upper end 19 which engages and closes with said cylinder as shown in Fig. 2. The sleeves 16 and 17 are thus maintained in spaced relation to each other and to the cylinder 11.

An upper collar 20 is threaded on the cylinder 11 and engages from above against said upper end 19 of sleeve 17 whereby to prevent upward displacement of said outer sleeve 17. The inner sleeve 16 terminates at its upper end 18 a distance below the upper end 19 of the outer sleeve 17, whereby to define a chamber 21; there being ports 22 opening from the chamber 21 through the outer sleeve 17 in a circumferential row.

The vertical passage 23 formed between the inner and outer sleeves 16 and 17 is blocked adjacent but short of the upper end 18 of said inner sleeve 16 by an annular spacer 24.

A circumferential row of ports 25 establish communication between the passage 26 (which passage exists between the cylinder 11 and inner sleeve 16) and the chamber 21.

A separate circumferential row of ports 27 is formed in the outer sleeve 17 below the spacer 24, establishing communication between the passage 23 and the outside of said outer sleeve 17.

It will therefore be seen that by reason of the above described porting and spacer arrangement as shown particularly in Fig. 2, matter within passage 23 can discharge through ports 27 to the outside of sleeve 17 at one level, while matter can discharge from within passage 26 through ports 25 into chamber 21 and thence pass to Q the exterior of said sleeve 17 through ports 22 at a level At its upper end the cylindrical housing 1 is fitted with above that of the ports 27. The purpose of this arrangement will be seen later.

The outside diameter of the outer sleeve 17 is slightly lesser than the inside diameter of the annular, inwardly 3 projecting flange 15. whereby an annular opening 23 exists between such parts.

At its lower end the inner sleeve 16 is formed with an annular, outwardly projecting flange 29 which terminates at its periphery a substantial distance from the bowl wall. Similarly, the outer sleeve 17 is formed at its lower end with an annular, outwardly projecting flange 3i spaced above the flange 29, and being of greater width; i. e., having greater radial projection and termihating adjacent but short of the bowl wall.

The flange 30 is spaced below the flange l5, while the flange 29 is spaced below the flange 30, whereby to define annular horizontal passages 31 and 32.

The flange 30 is formed, on the under side but short of its periphery, with an annular depending rib 33, whose purpose will hereinafter appear.

The space between the periphery of the annular flange 30 and the upper peripheral end of the bowl 12 forms an annular throat 34. Similarly, the space between the periphery of the annular flange 29 and the adjacent edge 5 of the rib 33 forms an annular throat 35. The throat 34 communicates with the passage 31, while the throat 35 communicates with the passage 32. In turn, the passage 31. communicates with the annular opening 28, while the passage 32 communicates with the passage 23.

A mixture delivery tube 36 of lesser diameter than the rotary cylinder 11 depends, in non-rotatable relation, centrally into said cylinder from above, passing through an upper end closure ring 37 in said cylinder.

The mixture delivery tube 36 is supported in a suitable 1..

manner, as by a mixture supply pipe 313 coupled to said tube at its upper end. The rotary cylinder 11 is formed adjacent but short of its lower end-i. e. a distance above the hub 9-with an internal restriction 3? which materially reduces the internal diameter of said cylinder so that at the point of such restriction it surrounds the lower end portion of the tube 36 with a relatively close running lit; the upper surface of the restriction 3? being dished or tapered upwardly and outwardly, as at ii). The restriction 39 separates or divides the interior of cylinder 11 into two portions, the lower one of which forms a relatively small chamber 41 at the bottom of said cylinder. A circumferential row of ports 42 opens through the cylinder 11 between said chamber 41 and the bottom portion of the bowl .112. The tube 36 terminates at its lower end in the chamber 41 above the ports 42.

A water supply pipe 43 is connected to the tube 36 above the closure. ring 37, and an internal passage 44 within the upper portion of the tube 36 establishes communication between water supply pipe 43 and a port r 45 which opens through said tube between passage 44 and the inside of the cylinder 11. With this arrangement water from the pipe 43 is delivered into the cylinder 11 without gaining access into the tube 36.

In a horizontal plane slightly below the annular flange 29 the cylinder 11 is formed with a circumferential row of holes 46, and radial tubes 47 are fixed in connection with the cylinder 11 in communication with the holes 46; the tubes thence projecting radially outwardly and terminating at their outer ends in upturned elbows 48. The annular depending rib 33 has an internal circumferential passage 49 therein, and the tubes 47 are connected in communication with said passage 49 by fittings F which are coupled to the elbows 48. With the foregoing arrangement communication is established between the inside of the cylinder 11 and the internal passage 49 in the rib 33.

A plurality of circuinferentially spaced nozzles 50 are secured to the annular flange 30 in communication with the passage 49; said nozzles extending radially outwardly to a termination near but short of the wall of the bowl 12 as shown in Figs. 3 and 5.

A plurality of circumferentially spaced, substantially full-height impeller fins 51 are fixed exteriorly on the cylinder 11 and extend radially therefrom to outer edges which abut the wall of the bowl in matching relation.

The upper. edges t he mpel er ns 5.1 a e ut (see. F n 6 for example) to matchingly and supportingly engage the flanges 29 and 39 from below; the purpose being to maintain said flanges, together with the sleeves 16 and 17, against downward displacement. Additionally, spacer screws 52 maintain the proper spacing between the flanges 29 and 30. The impeller fins 51, at the top and adjacent their inner edges, also include integral upstanding fingers 53 which project upwardly into the passage 26.

Other but relatively shorter impeller fins, 5 4 are sccurcd to the cylinder 11 equi-distantly between the fins 51; said shorter fins 54 terminating at their upper ends a distance below the flange 29, and at their outer edges abutting the wall of the bowl 12 in matching relation. Both the fins 51 and 54 seat at their lower ends on the bottom of the bowl 12.

The cylindrical housing 1 is formed, at the top and on the outside, with an annular channel 55, the top or" which is closed by a flat ring gear 56 driven by a pinion 57 on the upper end of a drive shaft 58. A plurality of circumferentially spaced paddles 59 are fixed to, and depend from, the fiat ring gear 56 for travel in substantially matching relation in the channel 55. At one point in the length thereof the bottom of the channel is formed with an opening 60 which delivers to a spout 6i.

The inner wall of the channel 55 is formed, at the top, with an annular slot 62 which embraces the horizontal plane of the top of the flange 15 on the centrifugal separator unit 4.

The outer sleeve 17 of the centrifugal separator unit 4 projects upwardly through the opening 5 in cover 2, extending a substantial distance into the dome 3. Within the dome 3 the same is separated into an upper chamber 63 and an intermediate chamber 64 by outwardly and downwardly inclined separator plates 65 and 66, respectively; said plates being annular and surrounding the sleeve 17 in adjacent but clearance relation.

At their outer edges the separator plates 65 and 66 are secured to the wall of the dome 3. The circumferential row of ports 22 registers with the chamber 63, while the circumferential row of ports 27 registers with the chamber 64. The chamber 63 has a bottom port 67 which delivers to a spout 63, while the chamber 64 has a bottom port 69 which delivers to a spout 70.

In operation of the above described centrifuge, the mixture to be separated, such as a mixture of water and pro-crushed or pro-ground vegetable substance, is delivered from the pipe 38 into the tube 36. discharging from the bottom of the latter into the mixture receiving chamber 41. The centrifugal separator unit 4 is driven at relatively high speed, and the mixture feeds from the chamber 41 through the ports 42 into the spinner bowl l2 1 at the bottom. In this manner the spinner bow] i2 is; maintained substantially full of the mixture at all times. and due to the relatively high speed of rotation the mutture stratifies in a radial direction. In other words. the material with the greatest specific gravity-4. e. the solids--seeks the outside, the water remains in an intermediate strata, and the oil is innermost.

As a result of such centrifugal separation of the constituents, by their specific gravities, and by reason of the fact that the mixture tends to flow upwardly in the spinner bowl 12, the solids deliver through the annular throat 34, flow in the passage 31, and thence pass up- 05 Wardly through the annular opening 23. From the an nular opening 28 the solids feed by centrifugal force on top of the annular flange 15 and discharge therefrom through the annular slot 62, thus entering the channel 55.

Once the solids are received in the channel 55 they are picked up by the paddles 59, moving under the influence of the driven ring gear 56, and are advanced in said channel to the bottom opening 60. When the solids reach the bottom opening 69 they fall into the spout 6,1 and are thus separately discharged from the centrifuge.

In order to assure that the solids do not pack, but maintain a semi-fluid condition for easy flow outof the centrifuge, water is constantly fed, in limited quantity, through the nozzles 50, such water flushing by centrifugal force through the annular throat 34 and thence following the path of the solids, as hereinbefore described. The water 'is fed to the nozzles 56 from the passage 49; the latter in turn receiving water from within the cylinder 11 by means of the tubes 47.

The cylinder 11 is fed water from the water supply pipe 43 by means of the internal passage 44 and port 45. The Water in the cylinder 11 does not escape to any material extent into the chamber 41; this by reason of the restriction 39, and the dished upper portion 40 thereof; the latter tending to act as a centrifugal slinger, causing up-flow of the water to a substantial extent at the point where it might otherwise escape downwardly alongside the tube 36. p

The Water in the mixture occupies the intermediate strata, and it flows through the annular throat 35, passage 32, and passage 23, discharging centrifugally through the ports 27 into the chamber 64 in dome 3. From said chamber the water escapes through the port 69 and is separately carried off by the spout 70.

The oil from the mixture, which occupies the innermost strata, travels upwardly in the passage 26 and discharges through the ports 25 into the chamber 21. From the chamber 21 the oil is discharged centrifugally through the ports 22 into the chamber 63; the oil feeding out of said chamber through the port 67 and being separately carried away by the spout 68.

The impeller fins 51 and 54 which radiate from the rotary cylinder 11 in the spinner bowl 12 assure that the mixture in said bowl is maintained against any static condition; i. e., is all constantly rapidly revolved with the bowl. v

In the foregoing manner the described centrifuge is extremely effective to accomplish the separation, by specific gravity, of a plurality of constituents of an initial mixture.

From the foregoing description it will be readily seen that there has been produced such a device as will substantially fulfill the objects of the invention,'as set forth herein. I

While this specification sets forth in" detail the present and preferred construction of the device, still in practice such deviations therefrom may be resorted to as do'not form adeparture from the spirit of the invention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new and useful, and upon which Letters Patent are desired: 1 v

1. In a centrifuge, a centrifugal separator unit comprising a vertically elongated cylinder closed at the lower end, supporting and drive means for the cylinder, an inverted, substantially conefshaped bowl. secured to and symmetrically surrounding the cylinder, means to feed a fluid mixture into the cylinder and fromthe same into the bowl adjacent the bottom of the latter, an annular inwardly projecting top flangesecured to. the bowl and defining a central opening, and'passage forming means secured in connection with the cylinder andextending from within the bowl upward through said central opening to a point above said topflange, said means forming a plurality of separate passages each having a throat in the bowl adjacent but below said top flange and an outlet opening above the throats, said throats being radially spaced in the bowl and the outlets vertically spaced above said throats. f

2. A centrifugal separator unit, as in claim 1, in which the radially spaced throats are disposed in different hori' zontal planes; the outermost throat being in the highest horizontal plane.

' 3. A centrifugal separator unit, as in claim 1, in which said mixture feeding means includes a tube depending into the cylinder from its upper end, and the lower portion of the cylinder having a port opening into the bowl.

4. A centrifugal separator unit, as in claim 3, including a restriction in the cylinder adjacent but above its lower end, whereby to form a mixture receiving chamber therebelow, the port leading from said chamber, and the tube extending through said restriction with relative close but relatively rotatable relation.

5. A centrifugal separator unit, as in claim 4, includ{ ing means to introduce water into the cylinder above said restriction, and means to feed Water from within the cylinder to one of said throats; said means including tubing communicating with and radiating from the cyl inder.

6. In a centrifuge, a centrifugal separator unit comprising a vertically elongated cylinder closed at the lower end, supporting and drive means for the cylinder, an inverted, substantially cone-shaped bowl secured to and symmetrically surrounding the cylinder, means to feed a fluid mixture into the cylinder and from the same into the bowl adjacent the bottom of the latter, an annular inwardly projecting top flange secured to the bowl and defining a central opening, the cylinder projecting upwardly through said central opening, a sleeve surroundingthe cylinder in spaced relation thereto, said sleeve projecting through said central opening from within the bowl to a closed upper end a distance above said top flange, the diameter of the sleeve being such that an annular opening exists between the same and said top flange, an annular outwardly projecting flange on the lower end of the sleeve within the bowl, said outwardly projecting flange being spaced below the top flange and terminating short of the bowl, and porting above the top flange establishing communication between the interior of the sleeve and the exterior thereof.

7. A centrifugal separator unit, as in claim 6, including nozzles on the periphery of said outwardly projecting flange, and means to feed water to said nozzles.

8. A centrifugal separator unit, as in claim 7, in which said water feeding means includes tubing communicating with and leading from a portion of the cylinder; the mixture feeding means including a tube depending into the cylinder, a restriction in the cylinder closely surrounding the tube intermediate its ends, said portion of the cylinder being above the restriction, and means to deliver water into said portion of the cylinder.

9. In a centrifuge, a centrifugal separator unit comprising a vertically elongated cylinder closed at the lower end, supporting and drive means for the cylinder, an inverted, substantially cone-shaped bowl secured to and symmetrically surrounding the cylinder, means to feed a fluid mixture into the cylinder and from the same into the bowl adjacent the bottom of the latter, an ,an-

nular inwardly projecting top flange secured to the bowl and defining a central opening, the cylinder projecting upwardly through said central opening, an inner and an outer sleeve surrounding the cylinder in spaced relation each to the other, said sleeves projecting through said central opening from within the bowl to closed upper ends a substantial distance thereabove, an annular outwardly projecting flange on the lower end of each sleeve within the bowl, said outwardly projecting flanges being vertically spaced, the outwardly projecting flange on the lower end of the outer sleeve having greaterprdjection than the corresponding outwardly projecting flange on the lower end of the inner sleeve, and passage forming means above the top flange establishing communication between the interior of each sleeve and the exterior o the outer sleeve at vertically spaced points.

10. In a centrifuge, a centrifugal separator unit comprising a vertically elongated cylinder-closed at the lower end, supporting and drive means for the cylinder, an in verted, substantially cone-shaped bowl secured to and symmetrically surrounding the cylinder, means to feed a fluid mixture into the cylinder and from the same into the bowl adjacent the bottom of the latter, an annular inwardly projecting top flange secured to the bowl and defining a central opening, the cylinder projecting upwardly through said central opening, an inner and an outer sleeve surrounding the cylinder in spaced relation each to the other, said sleeves projecting through said central opening from within the bowl to closed up per ends a substantial distance above said top flange, the diameter of the outer sleeve being such that an annular opening exists between the same and said top flange, an annular outwardly projecting flange on the lower end of each sleeve within the bowl, said outwardly projecting flanges and the top flange being spaced each from the other, the outwardly projecting flange on the lower end of the outer sleeve terminating short of the bowl but having greater projection than the corresponding outwardly projecting flange on the lower end of the inner sleeve, and passage forming means above the top flange establishing separate communication between the interior of each sleeve and the exterior of the outer sleeve at vertically spaced points.

ll. In a centrifuge, a centrifugal separator unit comprising a vertically elongated cylinder closed at the lower end, supporting and drive means for the cylinder, an inverted, substantially cone-shaped bowl secured to and symmetrically surrounding the cylinder, means to feed a fluid mixture into the cylinder and from the same into the bowl adjacent the bottom of the latter, an annular inwardly projecting top flange secured to the bowl and defining a central opening, the cylinder projecting up- I.

wardly through said central opening, an inner and an outer sleeve surrounding the cylinder in spaced relation each to the other, said sleeves projecting through said central opening from within the bowl to closed upper ends a substantial distance above said top flange, the I= diameter of the outer sleeve being such that an annular opening exists between the same and said top flange, an annular outwardly projecting flange on the lower end of each sleeve within the bowl, said outwardly projecting flanges and the top flange being spaced each from the other, the outwardly projecting flange on the lower end of the outer sleeve terminating short of the bowl but having greater projection than the corresponding outwardly projecting flange on the lower end of the inner sleeve, porting above the top flange establishing separate communication between the interior of each sleeve and the exterior of the outer sleeve at vertically spaced points, and a plurality of upstanding circumferentially spaced fins secured to the cylinder and radiating in the bowl.

12. A centrifugal separator unit, as in claim 11, in

which said fins, at their upper edges engage said outwardly projecting flanges in supporting relation to the sleeves.

13. In a centrifuge, a centrifugal separator unit comprising a vertically elongated cylinder closed at the lower end, supporting and drive means for the cylinder, an inverted, substantially cone-shaped bowl secured to and symmetrically surrounding the cylinder, means to feed a fluid mixture into the cylinder and from the same into the bowl adjacent the bottom of the latter, an annular annular outwardly projecting flange on the lower end of each sleeve within the bowl, said outwardly projecting flanges and the top flange being spaced each from the other, the outwardly projecting flange on the lower end of the outer sleeve terminating short of the bowl but having greater projection than the corresponding outill wardly projecting flange on the lower end of the inner sleeve, passage forming means above the top flange establishing separate communication between the interior of each sleeve and the exterior of the outer sleeve at vertically spaced points, nozzle means on the periphery of the outwardly projecting flange on the lower end of the outer sleeve, said nozzles discharging toward the bowl, and means to deliver water to said nozzles.

14. A centrifugal separator unit, as in claim 13, in which said last named means includes an annular rib on said outwardly projecting flange on the lower end of the outer sleeve, said rib having an internal passage and the nozzles communicating therewith, tubing communieating between said internal passage and one portion of the interior of the cylinder, said mixture feeding means being arranged to deliver into another portion of the cylinder, means separating said portions of the cylinder, and means to supply water into said one portion of the cylinder.

15. In a centrifuge, a centrifugal separator unit comprising a vertically elongated cylinder closed at the lower end, supporting and drive means for the cylinder, an inverted, substantially cone-shaped bowl secured to and symmetrically surrounding the cylinder, means to feed a fluid mixture into the cylinder and from the same into the bowl adjacent the bottom of the latter, an annular inwardly projecting top flange secured to the bowl and defining a central opening, the cylinder projecting upwardly through said central opening, an inner and an outer sleeve surrounding the cylinder in spaced relation each to the other, said sleeves projecting through said central opening from within the bowl to closed upper ends a substantial distance above said top flange, the diameter of the outer sleeve being such that an annular opening exists between the same and said top flange, an annular outwardly projecting flange on the lower end of each sleeve within the bowl, said outwardly projecting flanges and the top flange being spaced each from the other, the outwardly projecting flange on the lower end of the outer sleeve terminating short of the bowl but having greater projection than the corresponding outwardly projecting flange on the lower end of the inner sleeve, and passage forming means above the top flange establishing separate communication between the interior of each sleeve and the exterior of the outer sleeve, said passage forming means including vertically spaced ports in the outer sleeve; the centrifuge including a dome surrounding the outer sleeve above said top flange, said dome having vertically separated chambers therein, the vertically spaced ports on the outer sleeve being in register with corresponding chambers, and means to separately feed liquid from said chambers.

16. In a centrifuge, a centrifugal separator unit comprising a vertically elongated cylinder closed at the lower end, supporting and drive means for the cylinder, an in verted, substantially cone-shaped bowl secured to and symmetrically surrounding the cylinder, means to feed a fluid mixture into the cylinder and from the same into the bowl adjacent the bottom of the latter, an annular inwardly projecting top flange secured to the bowl and defining a central opening, the cylinder projecting upwardly through said central opening, an inner and an outer sleeve surrounding the cylinder in spaced relation each to the other, said sleeves projecting through said central opening from within the bowl to closed upper ends a substantial distance above said top flange, the diameter of the outer sleeve being such that an annular opening exists between the same and said top flange, an annular outwardly projecting flange on the lower end of each sleeve within the bowl, said outwardly projecting flanges and the top flange being spaced each from the other, the outwardly projecting flange on the lower end of the outer sleeve terminating short of the bowl but having greater projection than the corresponding outwardly projecting flange on the lower end of the inner 9 l0 sleeve, and passage forming means above the top flange the slot, and paddles on the ring gear depending into the establishing separate communication between the interior channel, the latter having a discharge opening in the of each sleeve and the exterior of the outer sleeve at verbottom thereof. tically spaced points; the centrifuge including a cylindrical References Cited in the file of this patent housing surrounding the centrifugal separator unit, said 0 housing having a circumferential slot in the same hori- UNITED STATES PATENTS zontal plane as the top flange, an annular channel about 974,075 King Oct. 25, 1910 the housing, the slot being in the inner wall of the chan- 2,256,316 Eddy Sept. 16, 1941 nel, a flat driven ring gear covering said channel above 2,622,795 Baxter Dec. 23, 1952 

